I've been with my partner for 26 years. We have 4 children together. And I've come to learn that he isn't the man I thought he was. The woman involved in this I knew he occasionally spoke to, didn't like it, but never thought anything of it. He then started talking down to me while constantly talking about her and how amazing she is. I got suspicious and went through his old phone, and what I found was at least 5 years of messages between them. I was physically sick and shaken as I read through them. They constantly said I love you to each other daily. She called him her husband, her forever husband, he would reply calling her mrs. A lot of sexual content shared, sharing about his day, asking to see her nude. Writing poems asking to taste what's between her legs. It got so intense that she ended her 10 year relationship and wanted him to leave me. He says it was nothing, no emotional affair or anything of the kind happened. It was all just words on a screen between 2 friends (she was his friends ex and known him for 30 years) this is apparently why it means nothing because they've been friends that long. He tells me i'm overreacting, which I know I'm not. I will add that we've been engaged for 14 years and now learned he's cheated for at least 5 of those. He gave the husband title away to another woman and thinks its nothing. Any advice would be greatly appreciated.